Roger Harrison Chair, EURADOS Working Group 9: Radiation Dosimetry - PowerPoint PPT Presentation

MELODI 7th Workshop, 9 – 11 November 2015 Helmholtz Zentrum München Next Generation Radiation Protection Research Out-of-field dosimetry in radiotherapy for input to epidemiological studies Roger Harrison Chair, EURADOS Working Group 9: Radiation Dosimetry in Radiotherapy Tuesday, 10 November 2015 Session 7: EURADOS-MELODI cross cutting themes

Radiotherapy A key component of cancer therapy • approximately 14 million new cancer cases per year worldwide • about half of all cancer treatments will involve radiotherapy (in the developed world) • approx. 1.3 million RT treatments y -1 in EU • Very large world wide radiotherapy patient cohort Wilkins, A. & Parker, C. (2010) Treating prostate cancer with radiotherapy Nat. Rev. Clin. Oncol. doi:10.1038/nrclinonc.2010.135

Recent developments have improved target dose distributions: Intensity Modulated Radiotherapy Tomotherapy Image Guided Radiotherapy Protons & Ions Total marrow irradiation protocol From: Beavis AW The British Journal of Radiology, 77 (2004), 285 – 295 Source: Philips Healthcare BUT: Radiotherapy also involves the irradiation of all parts of the body including healthy tissues and organs

Radiotherapy modalities: All have different implications for out-of-field doses “conventional” linear accelerator Tomotherapy Robotic arm systems GammaKnife Brachytherapy Proton therapy

Doses from radiotherapy & imaging systems CT On board imaging: kV and MV imaging systems on a linear accelerator

Adaptive radiotherapy planning using serial FDG-PET – CT imaging in a patient with stage IIIB NSCLC. PET in the management of locally advanced and metastatic NSCLC. Willem Grootjans, Lioe-Fee de Geus-Oei, Esther G. C. Troost, Eric P. Visser, Wim J. G. Oyen & Johan Bussink Nature Reviews Clinical Oncology 12, 395 – 407 (2015) doi:10.1038/nrclinonc.2015.75

The out-of-field dose to the patient from all sources - “the complete dose specification” ……………….. A complex synthesis of therapy and imaging exposures from numerous modalities and techniques Why generate the complete dose specification from therapy and imaging? • To inform risk/benefit considerations for the benefit of patients • For input to epidemiological studies of risks, benefits and outcomes o Second cancers o Cardiovascular disease o Other organ damage………….. • To study the effects of ionising radiation on humans, following on from the Japanese LSS

Four important attributes in the design of epidemiological studies of radiation-exposed populations*: Attribute Radiotherapy patient cohorts • 1. Population size adequate to meet approximately 14 million new statistical power considerations cancer cases per year worldwide • about half of all cancer treatments will involve radiotherapy (in the developed world) • 1.3 million radiotherapy treatments year -1 in EU • Very large world-wide radiotherapy patient cohort * Steven L. Simon and Martha S. Linet. Health Phys. 106(2):182-195; 2014

Attribute Radiotherapy patient cohorts 1.3 million RT treatments y -1 in EU 1. Population size adequate to meet statistical power considerations 2. Large enough average dose and a Doses vary from tens of Gy (target) to wide enough dose range to derive a tens of mGy dose-response relationship; * Steven L. Simon and Martha S. Linet. Health Phys. 106(2):182-195; 2014

Schematic dose-risk graph (after Hall 2008) Japanese LSS data Cancer risk cell kill bystander effects LNT threshold 0.01 0.05 2.5 10 Equivalent Dose / Sv

Japanese LSS data Cancer risk 0.01 0.05 2.5 10 Equivalent Dose / Sv

Attribute Radiotherapy patient cohorts 1.3 million RT treatments y -1 in EU 1. Population size adequate to meet statistical power considerations 2. Large enough average dose and a Dose vary from tens of Gy (target) to wide enough dose range to derive a tens of mGy (at ? Distance from target) dose-response relationship; 3. Understanding and capability to Radiotherapy target doses are determine or reliably estimate accurately calculated and delivered individual doses usually required for with rigorous supporting QA, and well specific organs documented, with planned patient follow-up. Out-of-field doses are not so extensively measured or calculated * Steven L. Simon and Martha S. Linet. Health Phys. 106(2):182-195; 2014

Attribute Radiotherapy patient cohorts 1.3 million RT treatments y -1 in EU 1. Population size adequate to meet statistical power considerations 2. Large enough average dose and a Dose vary from tens of Gy (target) to wide enough dose range to derive a tens of mGy (at ? Distance from target) dose-response relationship; 3. Understanding and capability to Radiotherapy target doses are determine or reliably estimate accurately delivered with rigorous individual doses usually required for supporting QA, and well documented. specific organs Out-of-field doses are not so extensively measured or calculated 4. Potential value of the study as Clinical need and basic radiation determined by public health, clinical, protection requirement for risk/benefit or societal concerns. judgements * Steven L. Simon and Martha S. Linet. Health Phys. 106(2):182-195; 2014

EURADOS Working Group 9: Radiation Dosimetry in Radiotherapy • Development of “the complete dose specification” from all sources of radiation to all parts of the body, delivered as part of radiotherapy planning & treatment • Develop & harmonise out-of- field dosimetry techniques in radiotherapy • Provide dosimetric input to second malignancy risk models and epidemiological studies

Measuring out-of-field doses from a paediatric brain tumour treatment (photons) Institute of Nuclear Physics (IFJ) and Centre of Oncology, Krakow Ruđer Bošković Institute , Clinical Hospital for Tumours & Clinical Hospital Centre, Zagreb

Measuring out-of-field doses from a paediatric craniospinal treatment (photons) Cranio-spinal irradiation at the Centre for Oncology, Krakow, and the Clinical Hospital for Tumours, Zagreb Passive detectors (TLD, RPL) positioned inside 5y and 10y old phantoms.

Measuring out-of-field doses from a paediatric brain tumour treatment using Gamma knife™ (stereotactic radiosurgery) Ruđer Bošković Institute , Clinical Hospital for Tumours & Clinical Hospital Centre Zagreb 2014

BOMAB (Bottle Manniquin Out-of-field dose Absorber) phantom experiments: differences between phantom University of Pisa & University Hospital measurements and of Santa Chiara, Pisa, 2011, 2012 calculation using a treatment planning Institute of Nuclear Physics (IFJ) and system Centre of Oncology, Krakow 2011, 2012

Some preliminary results……… Out-of-field dose measurement in a paediatric anthropomorphic phantom 10y IMRT treatment of paediatric brain tumour 100.000 Dose (Gy) for 40 Gy to target 10.000 1.000 0.100 0.010 0.001 -10 0 10 20 30 40 50 60 70 80 distance from isocentre / cm

Out-of-field dose measurement in a paediatric anthropomorphic phantom 10y IMRT treatment of paediatric brain tumour 100.000 Dose range of interest: Dose (Gy) for 40 Gy to target ~ 10 – 1000 mGy 10.000 1.000 0.100 0.010 0.001 -10 0 10 20 30 40 50 60 70 80 distance from isocentre / cm

Paediatric brain tumour treatment (photons) 100000 Head Body 3D-CRT (TLD) 10000 Dose comparison for 5y phantom IMRT (RPL) Total target dose = 40 Gy Dose (mGy) 1000 100 10 1 Organ / tissue

Paediatric brain tumour treatment (photons) 100000 10000 IMRT : total target dose = 40 Gy Dose (mGy) 1000 10 year 5 year 100 10 1 organ / tissue

Proton therapy dosimetry: Institute of Nuclear Physics (IFJ), Krakow • Out-of-field doses in a water tank • Brain tumour treatment simulation • Environmental neutron measurements with a variety of dosemeters

Schematic view of ten measurement positions around a 10-year-old paediatric phantom and experimental setup with Bonner spheres within the CCB-Krakow gantry room. A comprehensive spectrometry study of stray neutron radiation field in scanning proton therapy. Mares et al. (submitted to Int J Radiat Onc Biol Phys.)

H* (10 ) = 1.16 μSv.Gy -1 H* (10 ) = 2.67 μSv.Gy -1 H* (10 ) = 0.97 μSv.Gy -1

Craniospinal irradiation for medulloblastoma using passively scattered proton Absorbed beams dose distribution Second cancer mortality distribution Vary with age at exposure, attained age, gender, genetic profile….. Second cancer incidence distribution From: Nature Reviews Cancer Wayne D. Newhauser and Marco Durante Assessing the risk of second malignancies after modern radiotherapy JUNE 2011 VOLUME 11 438-448 .

Radiotherapy: the complete dose specification Photon Radiotherapy Proton Radiotherapy Radiotherapy Imaging & IGRT TPS Photon out-of- TPS Proton & neutron calculations field dosimetry in calculations out-of-field anthropomorphic Measurement Measurement dosimetry in Out-of-field phantoms of doses from of doses from Out-of-field anthropomorphic dosimetry kV imaging MV imaging dosimetry phantoms models models Molecular CT imaging: SPECT, PET Phantom & dosimeter Phantom & dosimeter Phantom & dosimeter development development development Complete dose specification